In the construction industry, shower drain assemblies are used to connect the base of a shower with an outgoing drain pipe. In both new construction and remodel projects, a first worker typically inserts a drain fitting downward into a pre-existing shower base drain hole. A second worker, located beneath the floor supporting the shower, e.g., in a basement or crawl space, attaches additional assembly pieces to the fitting to seal it against the shower base underside surface and/or surrounding structure. It is usually necessary for the first worker to hold the drain fitting steady from above while the second worker attaches the additional pieces from below.
U.S. Pat. No. 3,896,511 illustrates a typical arrangement in which a shower fitting 14 is inserted downward into an opening 11 in the base of a shower receptor 12. A discharge pipe 13 is connected to the fitting lower end. The fitting 14 includes a cylindrical body 16 having lateral threads about its exterior. Once the fitting is placed in the opening 11, a number of seal rings are placed from below up and around the cylindrical body. A nut 22 engages the body threads to secure the seal rings and fitting to the shower receptor 12. A flange 17 maintains the fitting in the shower receptor by providing a force on the shower base that opposes the force provided by the nut 22.
The device described in the '511 patent has a number of disadvantages, the most significant of which is that the '511 device can be difficult to seal. Rotation of the nut 22 against the seal rings tends to also rotate the seal rings and fitting which deters a good seal and further makes it difficult to tighten the nut. Further, a number of current drain assemblies are presently manufactured such that their threads are not perpendicular to their top flanges. This creates a situation in which the nut will tighten on one side or location, but not on the opposing side. This is a problem in that it leaves the uncontacted side unsealed and not in contact with the bottom of the shower base, thereby making a complete seal unattainable. Likewise, some of these current drains are manufactured such that the threading on the inside of the nut is not perpendicular as required.
Another problem with the '511 device is that it is annoying and time-consuming to install, since rotation of the nut 22 is not always easily accomplished. This is particularly true if the only access to the underside of the drain fitting is from a confined space in which the worker's arm and/or wrist cannot easily move to rotate and tighten the nut 22. In addition, this type of drain requires the additional person located above the drain fitting to hold the fitting in place while the first worker tightens the nut from below.
Although not applied to the shower drain art, U.S. Pat. No. 3,509,586 describes a sink strainer mounting means in which an annular carrier 16 is screwed to threads 8 on the exterior of a drain fitting lower outlet end 7. The carrier 16 includes three ears 20 extending laterally outward at locations spaced 120 degrees apart. Screws 22 are insertable through the ears 20 to provide an upward force to a pressure member 11. While this arrangement improves the operator's ability to effectuate a good sealing fit and further helps to reduce the frustration associated with screwing a large nut onto the fitting itself, the '586 arrangement still has the disadvantage of requiring the need to screw the carrier 16 onto the outlet end 7. This can still pose a problem in applications having restricted space.
U.S. Pat. No. 5,560,052 describes a garbage disposal assembly in which a cylindrical sink flange 60 is attached to a sink bottom 22 by screws 43 exerting an upward force on a backup ring 47. The sink flange includes an upper lip 82 that rests within the sink. The upward force of the mounting screws 43 is effectuated by inserting the mounting screws up through a mounting ring 42. The mounting ring 42 has restricted downward motion by abutting against a snap ring 50 attached around an inward ring groove 66 formed in the lower end of the sink flange 60. While this arrangement is easier to install, it is susceptible to damage and/or dysfunction should the snap ring 50 unseat from the sink flange 60 and/or become damaged.
Thus a need yet exists for an improved shower drain fitting that is easy to install even in confined spaces and that includes a robust means for being held in the base of a shower. The ideal assembly would further allow a single person to install the assembly and provide a good sealing fit. The present invention is directed to fulfilling these needs as well as others described below.